This two year CDC-funded project will help answer several of the critically important questions regarding social contacts, mixing patterns, and the spread of common infectious diseases in the school-age population. As reinforced by the recent novel H1N1 pandemic, infectious diseases spread efficiently through the school-age population and often arrive at unexpected times before pharmaceutical countermeasures such as vaccines and anti-viral medications are available to the general population. This project will provide data leading to improved understanding of how diseases such as influenza spread among children in school and between children and the community, will lead to more accurate information regarding when, where, and how to intervene using "non-pharmaceutical" and "pharmaceutical" interventions, and improve our ability to respond to pandemic influenza and other diseases in order to reduce illness, save lives, and reduce panic. The project uses both established "diary-based" methods and cutting-edge electronic tools, such as wireless proximity sensors, video, and GPS units to better document the contacts and mixing patterns of school-age children whether they are in school, at home, or in the community. This information will be combined with active disease surveillance and laboratory testing to better understand how and when children are exposed to and develop illness from contagious diseases. For access to schools, the project will use the School-Based Research and Practice Network, a unique program that links academic investigators with schools. The Network has linked more than 100 schools in 29 districts with a wide range of research projects in just the last 2 1/2 years. The project is led by Samuel Stebbins, MD, MPH at the University of Pittsburgh and Derek Cummings, PhD, MS, MHS at the Johns Hopkins Bloomberg School of Public Health. Drs. Stebbins and Cummings have previously collaborated on the Pittsburgh Influenza Prevention Project, a randomized trial studying non-pharmaceutical interventions which recruited more than 3000 elementary school students in Pittsburgh, created an absentee-based surveillance system, screened students for illness and tested them for influenza using RT PCR technology. The project includes experts in social science, infectious disease modeling, social media, peer to peer and sensor networks, and computer programming from the Public Health Dynamics Lab at the University of Pittsburgh and the University of Liverpool in England. It will work with a variety of schools in Pittsburgh and throughout Allegheny County, PA. With a population of more than 1.2 million, a broad range of demographic, economic, and environmental characteristics and a school system that is welcoming and supportive of research, the county is an ideal setting to study population and disease trends.